(PDB-697) Added docs/tests for new queryable nodes fields and operators

New fields are now available as part of the nodes endpoint that resulted
from moving the endpoint into the query engine. This commit tests and
documents those new fields
Merge pull request #987 from senior/ticket/master/pdb-697-doc-test-nodes-qe-change

(PDB-697) Added docs/tests for new queryable nodes fields and operators